Recently, the production of the semiconductor device using the mounting method of so called “face down method” is carried out. In the face down method, the semiconductor chip (hereinafter, it may be referred as “chip”) having electrodes such as bumps or so on the circuit surface is used, and said electrodes are bonded with the substrate. Therefore, the face of the opposite side of the circuit face of the chip (the backside of the chip) will be exposed.
The chip backside which has been exposed may be protected by an organic film. Conventionally, the chip having the protective film made of this organic film was obtained by coating the liquid resin on the wafer backside by a spin coat method, then drying and curing followed by cutting the protective film together with the wafer. However, the accuracy of the thickness of the protective film formed as such was not sufficient, hence the yield rate of the product declined in some case.
In order to solve the above problem, the chip protection film having the release sheet, and a protective film forming layer consisting of an energy ray curable component and a binder polymer component which are formed on said release sheet is proposed (Patent article 1).
Further, the semiconductor chip has become thinner and has higher density recently, thus even higher reliability is requested for the semiconductor chip mounted with the protective film when it is exposed to a harsh temperature condition.
According to the study by the present inventors, the chip protective film described in the patent document 1 shrunk when curing the protective film forming layer, and had problem of the semiconductor warpage or so in some case. Particularly, such problem was prominent for the extremely thin semiconductor wafer. When the semiconductor wafer warpage occurred, the wafer may be damaged, or the marking (the printing) accuracy to the protective film may decline. Also, for the chip protective film described in the patent document 1, when producing the chip with the protective film, the wafer with the protective film is adhered to the dicing sheet, and the wafer needs to be diced, hence the production steps are complicated.
Thus, the warpage of the wafer can be prevented by taking the constitution wherein the protective film forming layer cut out to a same shape in advance as the wafer is provided on the adhesive layer of the dicing sheet made of a base film and the adhesive layer, since the outer peripheral part of the sheet can be adhered and fixed to the ring frame. Also, the dicing can be carried out while being fixed as such, hence even after the curing of the protective film forming layer, there is no need to carry out the dicing by additionally adhering the dicing sheet, thus the production steps can be simplified.
[Patent Article 1] JP Patent Application Laid Open No. 2009-138026